The invention relates to new and useful improvements in expansion packers used in oil well drillings.
Expansion packers are used in test equipment which is secured to the lower end of a drill string and lowered down the well once it has been drilled as far as the oil or gas zone. These packers form part of the testing equipment and are used to shut off zones above oil or gas locations in order to stop contamination by water and the like while testing is taking place.
The drill string connects to the top plate of the packer and when the bottom of the drilling is reached, extra downward pressure on the string moves the top plate downwardly on the mandrel and expands the rubber packer outwardly to the walls of the drill hole thereby closing off the hole.
The mandrel maintains the integrity of the connection through the packer for sampling procedures, etc.
Conventionally, the packing elements are formed of upper and lower sections and a center section bonded together with the junctions being substantially perpendicular to the longitudinal axis of the packer and the upper and lower sections are usually of a higher durometer reading than the center section so that compression of the packer causes the center section to bulge outwardly. However, the junctions often break away or tear, destroying the effectiveness of the packer and it will be appreciated that considerable time and effort is wasted if the drill string has to be removed in order to replace a packer.